Final Report Summary - PROTONICS (Mechanistic aspects of protons in hard materials for clean energy applications)
Research on "clean energy materials" is an important field of materials science. The performance of alternative energy technologies depends on the properties of their component materials, and for the development of next-generation devices the discovery and optimization of new materials are critical to future breakthroughs. Such a development depends on an increased understanding of the fundamental aspects related to structure and dynamics of the most promising materials, however such knowledge is often lacking. In view of this lack of knowledge, the objective of this project is particularly to elucidate various key fundamental properties related to the structure and dynamics of proton-conducting oxides, targeted as electrolytes for intermediate-temperature fuel cells. The ultimate goal is to develop an atomic-scale understanding of the hydrogen diffusion mechanism and apply this knowledge to the rational design of new materials with better performance with respect to technological applications. The primary tools to this end involve the use of neutron and synchrotron x-ray scattering techniques, available at international large-scale research facilities, and vibrational spectroscopy (Raman and infrared), available at the host organisation, Chalmers University of Technology.
Overall the project has progressed well and the research team, including myself and to date four PhD students, have achieved most of the objectives for the period of interest with only quite small deviations from the original working plan. In particular, on the basis of additional funds from Swedish sources, I have been able to expand on the initial aims of the project. A key scientific result is the elucidation of the short-range structure and dehydration mechanism of the proton conducting oxide Ba2In2O5, using a combination of neutron scattering and vibrational spectroscopy, as published recently in two important papers recently. Another recent key result is the observation of rotational motions of pyramidal SiH3- ions in the two silanid materials KSiH3 and RbSiH3, using quasielastic neutron scattering. The advancement of the compositon-structure-dynamics relationships in perovskite type oxides and in alkali silanides are central to those of solid-state ionic conductors generally, and an understanding of such relationships is expected to provide insights on other hydrogen-containing materials, such as complex metal hydrides, for example. Similar issues concerning the local structure and dynamics of hydrogen in solid materials are central to the properties of related solid-state compounds used in for example solar cells, water splitting reactions, and batteries, to mention a few. Furthermore, I have, during the course of the project, been actively involved in a wide range of teaching, dissemination, and outreach activities. Examples include the teaching and development of new courses, presentations at conferences and workshops, peer-reviewing of research proposals and papers, and engagement as board member or chair of several committees. In sum, these results and activities have allowed me to build further on my academic career.
Overall the project has progressed well and the research team, including myself and to date four PhD students, have achieved most of the objectives for the period of interest with only quite small deviations from the original working plan. In particular, on the basis of additional funds from Swedish sources, I have been able to expand on the initial aims of the project. A key scientific result is the elucidation of the short-range structure and dehydration mechanism of the proton conducting oxide Ba2In2O5, using a combination of neutron scattering and vibrational spectroscopy, as published recently in two important papers recently. Another recent key result is the observation of rotational motions of pyramidal SiH3- ions in the two silanid materials KSiH3 and RbSiH3, using quasielastic neutron scattering. The advancement of the compositon-structure-dynamics relationships in perovskite type oxides and in alkali silanides are central to those of solid-state ionic conductors generally, and an understanding of such relationships is expected to provide insights on other hydrogen-containing materials, such as complex metal hydrides, for example. Similar issues concerning the local structure and dynamics of hydrogen in solid materials are central to the properties of related solid-state compounds used in for example solar cells, water splitting reactions, and batteries, to mention a few. Furthermore, I have, during the course of the project, been actively involved in a wide range of teaching, dissemination, and outreach activities. Examples include the teaching and development of new courses, presentations at conferences and workshops, peer-reviewing of research proposals and papers, and engagement as board member or chair of several committees. In sum, these results and activities have allowed me to build further on my academic career.